It's a global day of action to scale back on fossil fuels—both symbolically and politically. All around the world, thousands of participants are expected to fill the streets on sustainable forms of transport (including feet), and present their leaders with demands for climate action.

Participants in September's No Impact Week with YES! will round out a one-week collective carbon cleanse by participating in Moving Planet Day through activities like cycling from a problem (think oil refinery) to a solution (solar power plant); throwing neighborhood parades to get communities excited about carless transportation; delivering petitions to local leaders; or anything else they come up with.